Delustered superpolyamide articles and process of making same



Patented Mar. 9, 1954 DELUSTERED SUPERPOLYAMIDE ARTICLES AND PROCESS OF MAKING SAME Jean Chezaud, Lyons, France, assignor to Societe Rhodiaceta, Paris, France, a company of France No Drawing. Application April 4, 1952, Serial No. 280,672

Claims priority, application France April 11, 1951 9 Claims. 1

In order to give a mat appearance to filaments having a basis of superpolyamides it is known to incorporate therein inert pigments such as titanium dioxide. According to the proportion of these delustering agents which is added, more or less pronounced mat effects are obtained. Thus. for example, for proportions of the order of 0.1 and 0.5% of delustering agents threads are obtained known as "semi-mat that is to say, presenting only a slightly pronounced mat appearance, whereas for higher proportions, ranging up to 0.5% to 5% for example, threads are obtained which are properly speaking called mat and which no longer show any appreciable luster.

It has also been definitely recognised that filaments having a basis of superpolyamide have a certain sensitivity to actinic light, which sensitivity is still further increased by the addition of delustering agents and which is the more marked the higher is the proportion of the delustering agents.

It has been attempted to protect filaments of the type in question from the deleterious effect of light by incorporating in them protective agents and amongst these, the salts of manganese have been specially suggested, particularly the lactate. It has likewise been known to incorporate certain salts of copper, for example the acetate or the stearate, in these materials in the course of the manufacture from them of shaped objects so as to protect the articles obtained from degradation by the action of heat and light. These difierent protective agents are always used in very small quantities as one very soon reaches a degree of improvement which cannot be exceeded, and an increase in the amount of the protective agent above that so required brings about a colouration of the articles which becomes more marked on prolonged exposure to actinic light.

The present invention relates to the manufacture of shaped articles which have a particularly strong resistance to degradation by the action of actinic light, and having a basis of superpolyamides of the kind known as mat, that is to say, containing 0.5 to 5% of the delustering agents. The articles made according to this invention are characterised by the fact that they contain small proportions of both manganese and copper ions.

It has been found in a most unexpected manner that articles of superpolyamides which contain at the same time both manganese ions and copper ions are much less sensitive to actinic light than the articles containing the same proportion of manganese ions alone or of copper ions alone.

The invention is particularly valuable in the case of filaments and it has been found in the most surprising manner that the resistance of such filaments to the action of light is practically just as high as that of similar but lustrous filaments, that is to say, of filaments not containing delustering agents. This effect has never previously been obtained by the addition either of manganese ions or of copper ions. It has also been observed that the simultaneous addition of these two ions does not cause any appreciable improvement in the behaviour of lustrous filaments, which is a truly inexplicable fact and likewise equally of the semi-mat filaments themselves, namely, those containing less than about 0.5% of the usual delustering agents, particularly those comprising titanium dioxide which were hitherto considered to be responsible for the unsatisfactory character of these pigmented objects underthe action of actinic light.

The figures which are given hereinafter bring out clearly these characteristics.

The manganese and copper ions can be intro duced in different forms, in particular as hydroxides or as salts of weak acids. By weak acids are to be understood those which are not capable of having a degrading action on the superpolyamides when the salts used are subsequently hydrolysed in the course of further treatments after the incorporation of these salts. The two protective compounds can be incorporated in the shaped articles at various stages of their manufacture or of their transformation or of their making up into final articles.

These substances can for example be introduced into the starting materials or the intermediate products used for obtaining'the superpolyamides. This method of working ensures a homogeneous distribution of the protective substances throughout the mass without interfering in any way with the polycondensation.

The protective substances can be added to the mass which is intended to be formed into various articles, that is to say, to the melted mass (e. g. in the case of spinning in the molten state) or to a mass having the superpolyamide in the dispersed state as, for example, the dissolved state, the product then being separated from the vehicle by evaporation of the said vehicle or by coagulation (for example, in the case of dry spinning or in the case of wet spinning, respectively).

Likewise in the case of articles which have already been formed or pre-formed the protective substances can be incorporated at any appropriate stage of their subsequent treatment. for example, particularly in the case of filaments in the form of skeins or cakes or enrolled on bobbins or on any other suitable support, by immersing them in a bath containing the compounds containing the two ions in the dispersed state, in such a manner that these compounds become superficially impregnated on the filaments or penetrate to a certain depth therein which is particularly the case when the said baths contain swelling agents for the superpolyamides.

Finally, the operation just described can be carried out not only on the unworked filaments but also on manufactured articles which have been made from them, as for example fabrics, knitted materials, felts, etc.

Absolute values for the best proportion of the metallic ions to be incorporated cannot be given as this proportion depends on numerous factors, and above all, on the nature of the superpolyamide, on that of the delustering agent and on the proportion of the latter. Likewise one cannot give exact figures with regard to the relative proportions of each ion with regard to the other as here also various factors play a part.

It has, however, been established that the most favourable quantities of manganese ions or copper ions are between 0.001 and 0.04% for the first and between 0.001 and 0.01% for the second, the ratio between the quantity of manganese to that of copper being advantageously comprised between 1 and 4. Any technician can very easily determine by simple trials the most advantageous quantities for any particular case.

The invention is herein described in more detail in relation to the use by way of example of titanium dioxide as delustering agent, as this is the agent most frequently used and because the results in that case are particularly valuable.

As stated above the invention is more especially applicable to filaments and particularly to fine filaments namely, those having a titre between 0.5 and 6.0 deniers, whether they are assembled in the form ofmulti-filament threads or whether they are present in the form of fibres. It can, however, be also used for filaments or articles having a larger cross-section and in particular for mono-filaments or artificial horsehairs, for reeds, for tubes, for ribbons, for foils, for extruded materials of non-circular crosssections, for coatings for wires, for foils or films, or for moulded articles, etc.

Amongst the superpolyamides from which articles can be formed according to the present invention mention may be made particularly of those formed by polycondensation between an a-w-diamine and an a-w-dlacld (polyhexamethylene adipamide and polyhexamethylenesebacamide in particular) those formed by the autopolycondensation of an w-amino-carboxylic acid (for example, G-amino-caproic acid and 11- amino-undecanoic acid) or those formed by the interpolycondensation of these different starting materials (or their derivatives suitable for forming amides, as for example in particular the lactams of the w-aminoacids).

The invention relates also to the case where the superpolyamide articles according to the invention are not present solely as such but are associated with articles of an analogous kind but of a difierent nature, as for example in the case where textile articles are used in which the filaments of superpolyamides are associated with filaments of natural origin such as cotton, linen, silk or schappe or artificial filaments, such as rayon or fibranne, or synthetic filaments such as superpolyesters of polyvinyl derivatives.

The following examples which are given only by way of illustration and are not in any way limitative make plain the nature of the present invention.

EXAMPLE 1 A thread is manufactured from 13 filaments of polyhexamethylene adipamide with a total denier of 40 containing 3% by weight of titanium dioxide, 0.03% of manganese lactate having 1 molecule of water of crystallisation and 0.008% of copper acetate.

vA comparison thread is manufactured prepared in the same manner from the same constituents except that it contains neither the manganese lactate nor the copper acetate.

Two other comparison threads are also manufactured prepared in the same manner except that 0.038% of the aforesaid crystalline manganese acetate is added to the one and 0.038% of copper acetate is added to the other (this last named thread is coloured green).

A fifth comparison thread is also manufactured in the same way and of the same composition except that it does not contain the titanium dioxide; this thread is therefore a lustrous thread.

The five kinds of thread thus obtained are woven into five identical voiles which are exposed for some months in summer under the same conditions both to the open air and in a glass case. The dynamometric resistance of the five fabrics are then measured.

1. Fabric exposed to the open air At the end of one month's exposure the following results were obtained based on as the value for the resistance of the exposed fabric formed from the first test thread.

At the end of two months exposure figures are obtained of the same relative order of magnitude.

2. Fabric exposed in a glass case At the end of four months exposure the following figures were obtained, the figure of 100 again being used to denote the resistance of the exposed fabric formed of the first test thread,

A value of for the resistance of the fabric formed of the thread containing copper,

A value of 200 for the resistance of the fabric formed of the thread containing, manganese,

A value of 230 for the resistance of the fabric formed of the thread containing copper and manganese,

A value of 220 for the resistance of the fabric formed of the brilliant thread.

EXAMPLE 2 A bath is prepared containing 800 parts of water, 200 parts of pure formic acid, 2 parts of copper acetate and 2 parts of manganese lactate crystallised with 1 molecule of water. A small skein formed of threads having 23 filaments of superpolyamide obtained by starting from caprolactam having a titre of '70 deniers and containing 3 parts by weight of titanium dioxide is immersed in this bath at a temperature of 20 C. The small skein is then Withdrawn from the bath, dried in the air, and carefully washed with a solution of 5 parts of caustic soda in 100 parts of water, rinsed with soft water and again dried in the air. This operation is repeated three times.

The thread thus treated is exposed for 300 hours to the light of a lamp rich in ultra-violet rays. at the same time as a comparison thread of the same type which has not undergone this treatment.

The resistance of the two kinds of exposed threads is then measured. The treated thread and the comparison thread showed resistances, the ratio of which is comparable to that of the resistances of the fabrics of Example 1 made with the corresponding threads.

What I claim and desire to secure by Letters Patent is:

1. An article made from a delustered synthetic linear condensation superpolyamide having the intralinear recurring group --CONH and capable of being formed into fibres, said superpolyamide containing from 0.5 to 5% of titanium dioxide as the delustering agent, between 0.001% and 0.04% of manganese ions and between 0.001% and 0.01% of copper ions.

2. An article according to claim 1, in which the said superpolyamide is made from a diamine and a dibasic carboxylic acid.

3. An article according to claim 1, in which the said superpolyamide is made from an aminoacid.

4. An article according to claim 1, in which the said superpolyamide is made from an amideforming derivative of an aminoacid.

5. An article according to claim 1, in which the said superpolyamide is polyhexamethylenedipamide.

6. An article according to claim 1, in which the said superpolyamide is made from epsiloncaprolactam.

7. A process for the manufacture of an article from a delustered synthetic linear condensation superpolyamide having the intralinear recurring group -CONH-- and capable of being formed into fibres, comprising incorporating in the said superpolyamide from 0.5 to 5% of titanium dioxide as the delustering agent, between 0.001% and 0.04% of manganese ions and between 0.001% and 0.01% of copper ions.

8. A process according to claim '7 comprising incorporating titanium dioxide and manganese and copper ions in the polyamide-forming composition, and heating the said composition under polycondensing conditions.

9. A process according to claim 7 comprising immersing titanium dioxide delustered shaped articles in an acid solution containing both manganese and copper ions.

JEAN CHEZAUD.

No references cited. 

1. AN ARTICLE MADE FROM A DELUSTERED SYNTHETIC LINEAR CONDENSATION SUPERPOLYAMIDE HAVING THE INTRALIRIEAR RECURRING GROUP -CO-NH- AND CAPABLE OF BEING FORMED INTO FIBERS, SAID SUPERPOLYAMIDE CONTAINING FROM 0.5 TO 5% OF TITANIUM DIOXIDE AS THE DELUSTERING AGENT, BETWEEN 0.001% AND 0.04% OF MANGANESE IONS AND BETWEN 0.001% AND 0.01% OF COPPER IONS. 